const user = { name: "张三", age: 20 };
const { name, age } = user;
console.log(name);
console.log(age);
const arr = ["red", "green", "blue"];
const [RED, GREEN, BLUE] = arr;

function f1(title = "Untitled", width = 200, height = 200) {
  console.log(`${title}:${width}:${height}`);
}

f1("hello", undefined, 400);
function f2({title = "Untitled", width = 200, height = 200}) {
  console.log(`${title}:${width}:${height}`);
}
f2({width : 400});